Unitary presser bar spring regulating devices



Feb. 14, 1967 P. LESORT 3,303,804

UNITARY PRESSER BAR SPRING REGULATING DEVICES Filed Oct. 15, 1964INVENTOR.

PAUL LESORT ATTORNEY United States Patent 3,303,804 UNITARY PRESSER BARSPRING REGULATING DEVICES Paul Lesort, Freneuse, France, assignor to TheSinger Company, New York, N.Y., a corporation of New Jersey Filed Oct.15, 1964, Ser. No. 404,048 3 Claims. (Cl. 112235) This invention relatesto sewing machines and more particularly to a unitary regulating devicefor adjusting or regulating the pressure which a presser bar springapplies to the presser bar of a sewing machine.

Presser bar spring regulating devices are old and well known and in factUnited States Patent No. 3,055,326 shows a device for regulating thespring pressure of a presser bar spring. However, prior art presser barspring regulating devices have been more or less built into the sewingmachine and were not constructed as a unit that could easily be appliedto and removed from a sewing machine. Therefore, one of the primaryobjects of the present invention is to provide an improved presser barspring regulating device of the type herein shown that can be assembledas a unit and then easily applied to or removed from a sewing machine.

Another object of the invention is to provide an improved presser barspring regulating device which is constructed from a few simple partsthat can be manufactured economically.

A still further object of the invention is to provide an improvedunitary spring regulating device for the presser bar spring of a sewingmachine.

With the above and other objects in view, as will hereinafter appear,the invention comprises the devices, combinations and arrangements ofparts hereinafter set forth and illustrated in the accompanying drawingsof a preferred embodiment of the invention, from which the severalfeatures of the invention and the advantages attained thereby will bereadily understood by those skilled in the art.

In the drawings:

FIG. 1 is a fragmentary elevational end view of a sewing machineequipped with a unitary presser bar spring regulating device embodyingthe present invention, the face plate of the sewing machine having beenremoved to show the internal construction,

FIG. 2 is a horizontal sectional view taken substantially on the line 22of FIG. 1, but showing the face plate,

FIG. 3 is a vertical sectional view taken substantially on the line 3-3of FIG. 1,

FIG. 4 is a front elevational view showing the unitary presser barspring regulating device of this invention before it has been applied toa sewing machinne, and

FIG. 5 is an exploded perspective view showing certain parts of themechanism illustrated in FIGS. 1 through 4.

Referring more particularly to FIG. 1 of the drawings, there is shown aportion of a sewing machine 16 having a work support 17 fitted with athroat plate 18 through which projects a feed dog 19. A presser foot 21carried by the lower end of a presser bar 22 cooperates with the feeddog 19 to hold and forward work (not shown). A midportion of the presserbar 22 is vertically slid-able in a bore 23 formed in a lower portion ofthe head 24 of the sewing machine 16, and the upper end of the presserbar 22 is slidably mounted in a bore 26 in a boss 27 formed integralwith the upper end of the head 24. Secured, as by a screw, to thepresser bar 22 is a collar 28 having a radially extending finger 29which is slidably received in a slot 31 formed in the head 24. The slot31 and the finger 29 prevents the presser bar 22 from turning and theslot 31 also accommodates a presser lifter 32 which -is fulcrumed on apivot screw 33 threaded into a boss formed in the head 24. When thelifter 32 is raised, it lifts the presser bar 22 against the downwardbias of a helical compression spring 36 coiled around the presser bar22. The lower end of the spring 36 abuts the upper end of the collar 28,and the upper end of the spring 36 is engaged by a member presently tobe described. A face plate 37 swings on a single hinge screw 38 and whenthe face plate 37 is closed, it encases most of the previously describedmechanism as well as the unitary presser bar regulating device 44presently to be described.

The unitary presser bar regulating device 44, as best shown in FIGS. 4and 5, comprises essentially six parts, namely, a guide member 45, twoscrews 46-46 for securing the member 45 to the sewing machine boss 27, aspring abutment bracket 47 slidably mounted on the member 45, anadjusting knob 48, and a shouldered pivot stud or screw 49 for turnablymounting the adjusting knob 48 on the guide member 45.

The guide member 45 is in the form of an elongated rectangularparallelepiped having adjacent to its upper end a pair of unthreadedholes 51-51 for receiving the mounting screws 46-46, and toward itslower end a threaded hole 52 for accommodating the threaded end of thepivot screw 49. The lowermost end of the member 45 is bifurcated toprovide an open ended slot 53. The upper end of the spring abutmentbracket 47 is formed with a horizontally extending arm 61, the free endof which is bifurcated to form abutment fingers 62-62 and the main body63 of the bracket 47 is in the form of a crosshead having facingparallel grooves 64 and 66 for slidably mounting the bracket 47 on themember 45. The wall 67 of the bracket 47 between the two grooves 64 and66 is formed with a struck out follower 68 which, as best seen in FIG.3, is long enough to pass through the slot 53 and extend beyond thefront portion of the bracket 47.

The adjusting knob 48, which has a central hub-aperture 71, is similarto and serves the same purpose as the pressure regulating member shownin United States Patent No. 3,055,326, supra, and the knob 48 is formedon its inner side with a spiral cam track 72 and, when the unitaryregulator device 44 is assembled, the cam track 72 is disposedcontiguous to the guide member 45. As best illustrated in FIG. 5, thecam track 72 has a plurality of angularly spaced peripheral notches 72D,721, 722, 723, 724, 72-5, 726, 727, and 728, each notch being disposedat a different radial distance from the axis of the pivot stud 49. Thecam track 72 also has a substantially radial wall 73 extending from theradial notch 72D nearest the axis of the pivot stud 49 to the outerperiphery of the cam track 72 adjacent to the notch 728 that is mostremote from the axis of the pivot stud 49. The follower 68 extendsthrough the open ended slot 53 and tracks the periphery of the cam track72 to seat in any one of the selected peripheral notches 72D, 721, 722,723, etc. The distance of the selected notch in which the follower 68 isseated from the axis of the pivot stud 49 determines the position of theabutment fingers 62-62 on the presser bar 22 and thus influences thecompression applied to the spring 36. When the follower 68 rests innotch 72D, the fingers 62 engage the presser bar 22 at a high locationand thus the spring 36 is relaxed. In this position the presser foot 21is not forced against the feed dog 19 and the sewing machine 16 may beused for darning. As the knob is turned so that the follower 68 restssuccessively in the notches 721, 722, 72-3, etc., the spring 36 issuccessively compressed until, when the follower rests in notch 728, thepresser foot 21 presses on the feed dog 19 with maximum pressure.

The outer face of the knob 48 is formed with a frustoconical dial 76having indicia D, 1, 2, etc-8 corresponding to each of the peripheralnotches 72D, 721, 722,

723, etc. of the cam track 72. Preferably the indicia corresponding witheach notch is disposed on the dial at an angle of approximately 90 in acounterclockwise direction as viewed in FIG. 1 from the portion of thenotch to which it corresponds.

The unitary presser bar spring regulator device 44 is applied to thesewing machine 16 in the following manner. First, the adjusting knob 48is mounted on the guide member 45 by passing the pivot screw 49 throughthe hub aperture 71 and by then threading the screw 49 into the threadedhole 52. Next the bifurcated lower end of the guide member 45 is moveddownwardly into the grooves 6466 until the follower 68, which passesthrough the slot 53 engages the cam track 72. Then the abutment fingers62-62 are placed on top of the spring 36 and the guide member 45 isfastened to the boss 27 by means of the screws 46-46. As soon as this isdone, the pressure with which the presser foot 21 engages the feed dog19 can be adjusted by turning the knob 48. Closing the face plate 37completely covers the unitary presser bar spring regulating device 44.

Having thus set forth the nature of the invention, what is claimedherein is:

1. A unitary regulating device for regulating the pressure which apresser bar spring applies to the presser bar of a sewing machine, saidunitary regulating device comprising, an elongated apertured guidemember provided at one end with an open ended slot, an adjusting knob, acam track on said knob, means for pivotally mounting said knob on saidguide member, an abutment bracket entirely supported by and slidablymounted on said guide member, an arm on said bracket adapted to engagesaid presser bar spring, a cam follower formed on said bracket andpositioned to extend through the open ended slot in said guide member toengage the cam track on said knob, and means for securing said guidemember to the said sewing machine.

2. A unitary regulating device for regulating the pressure which apresser bar spring applies to the presser bar of a sewing machine, saidunitary regulating device comprising, an elongated apertured guidemember provided at one end with an open ended slot, an adjusting knobformed on one face with a dial and on its other face with a cam track,means for pivotally mounting said knob on said guide member, an abutmentbracket having a pair of facing parallel grooves for slidably mountingsaid bracket on said guide member, an arm bifurcated to form a pair offingers extending outwardly from said bracket and adapted to engage saidpresser bar spring, a cam follower formed on said bracket and positionedto extend through the slot in said guide member to engage the cam trackon said knob, and means for securing said guide member to the saidsewing machine.

3. A unitary device for regulating the pressure, which a presser barspring applies to the presser bar of a sewing machine, said device beingadapted to be assembled as a unit and applied to or removed from asewing machine as a unit, and said device comprising an aperturedelongated rectangular parallelepiped shaped guide member provided at oneend with an open ended slot, an adjusting knob formed on one face with adial and on its other face with a cam track, means pivotally mountingsaid knob on said guide member, an abutment bracket having spaced meansfor embracing said guide member and thereby slidably mounting saidbracket on said guide member, finger means carried by said bracket andadapted to engage said presser bar spring, a cam follower formed on saidbracket and positioned to extend through the slot in said guide memberto engage the cam track on said knob, and means securing said guidemember to said sewing machine.

References Cited by the Examiner UNITED STATES PATENTS 2,554,970 5/ 1951Adler 112-235 2,874,663 2/1959 Matugas 1l2-236 3,055,326 9/1962 Greulick112235 3,089,447 5/1963 Shuman l12 235 PATRICK D. LAWSON, PrimaryExaminer.

1. A UNITARY REGULATING DEVICE FOR REGULATING THE PRESSURE WHICH APRESSER BAR SPRING APPLIES TO THE PRESSER BAR OF A SEWING MACHINE, SAIDUNITARY REGULATING DEVICE COMPRISING, AN ELONGATED GUIDE MEMBER PROVIDEDAT ONE END WITH AN OPEN ENDED SLOT, AN ADJUSTING KNOB, A CAM TRACK ONSAID KNOB, MEANS FOR PIVOTALLY MOUNTING SAID KNOB ON SAID GUIDE MEMBER,AN ABUTMENT BRACKET ENTIRELY SUPPORTED BY AND SLIDABLY MOUNTED ON SAIDGUIDE MEMBER, AN ARM ON SAID BRACKET ADAPTED TO ENGAGE SAID PRESSER BARSPRING, A CAM FOLLOWER FORMED ON SAID BRACKET AND POSITIONED TO EXTENDTHROUGH THE OPEN ENDED SLOT IN SAID GUIDE MEMBER TO ENGAGE THE CAM TRACKON SAID KNOB, AND MEANS FOR SECURING SAID GUIDE MEMBER TO THE SAIDSEWING MACHINE.